WCF专题系列（4）：深入WCF寻址Part 4—自定义消息筛选器

定义行为扩展

接下来定义一个行为扩展元素，这里定义了一个Characters的属性，用来在配置文件中指定消息过滤器中用到的特殊字符，如下代码所示：

/// <summary>
/// Author: TerryLee
/// Url: http://www.cnblogs.com/terrylee
/// </summary>
public class FilteringEndpointBehaviorExtension
    : BehaviorExtensionElement
{
    protected override object CreateBehavior()
    {
        MessageFilter addressFilter = 
            new SpecialCharactersMessageFilter(Characters);
        MessageFilter contractFilter = 
            new MatchAllMessageFilter();

        return new FilteringEndpointBehavior(addressFilter, contractFilter);
    }

    public override Type BehaviorType
    {
        get 
        { 
            return typeof(FilteringEndpointBehavior);
        }
    }

    [ConfigurationProperty("characters", 
        DefaultValue = "terrylee", IsRequired = true)]
    public String Characters
    {
        get {
            return base["characters"].ToString(); 
        }
        set { 
            base["characters"] = value; 
        }
    }
}